(i) Field of the Invention
The present invention relates to an oxidation-reduction potentiometer which measures the oxidation-reduction potential of any type of water including domestic water, industrial water, natural water and a scientific solution conveniently and accurately.
(ii) Description of the Related Art
In recent years, there is provided or disclosed an oxidation-reduction potentiometer that immerses a working electrode which comprises a noble metal such as platinum (Pt) or gold (Au) and a reference electrode which comprises sodium chloride (NaCl) or potassium chloride (KCl) and has a metal portion formed of silver (Ag) and silver chloride (AgCl) immersed in a gelled or liquid internal liquid in a test liquid to measure a voltage between the working electrode and the reference electrode which is generated from an oxidation-reduction reaction.
The oxidation-reduction potentiometer presents an oxidation-reduction potential value through processes such as amplification and A/D conversion, while retaining the voltage between the working electrode and the reference electrode, i.e., the difference between a potential generated from the working electrode and a potential generated from the reference electrode as it is (refer to Patent Publication 1 or Patent Publication 2, for example).
Patent Publication 1
Japanese Patent Laid-Open Publication No. 64275/1999
Patent Publication 2
Japanese Patent Laid-Open Publication No. 9566/1999
However, the oxidation-reduction potentiometer has problems that nonlinearity and repeatability of the potentials generated from the electrodes with respect to a given concentration of substance are unsatisfactory due to instability of the reaction between the metal electrodes and the test liquid and that it takes a long measuring time.
Thus, an object of the present invention is to solve the above problems of the prior art and provide an oxidation-reduction potentiometer having its convenience improved by an improvement in measurement accuracy, a reduction in measuring time, and the like.